554 research outputs found
HFB calculations with a microscopic pairing interaction
Hartree-Fock-Bogolyubov (HFB) calculations making use of a recently proposed
microscopic effective pairing interaction are presented. The interaction was
shown to reproduce the pairing properties provided by the realistic
force very accurately in infinite matter. Although finite-ranged and non-local,
it makes 3D HFB calculations in coordinate space tractable. As a first
application, basic pairing properties of calcium isotopes in their ground-state
are studied. By comparing the results with those obtained using a standard
Density-Dependent Delta Interaction, the crucial isovector character of the
microscopic interaction is highlighted.Comment: 6 pages, 6 figures. Proceedings of the Conference on Nuclei at the
Limits, ANL, 2004. They will be published in the AIP Conference Proceedings
Serie
Exotic nuclear phases in the inner crust of neutron stars in the light of Skyrme-Hartree-Fock theory
The bottom part of the neutron star crust is investigated using the
Skyrme-Hartree-Fock approach with the Coulomb interaction treated beyond the
Wigner-Seitz approximation. A variety of nuclear phases is found to coexist in
this region. Their stability and relative energies are governed by the Coulomb,
surface and shell energies. We have also found that a substantial contribution
is coming from the spin-orbit interaction.Comment: 4 pages, 1 eps figure, Talk at the 17th Nuclear Physics Divisional
Conference of the EPS: Nuclear Physics in Astrophysics, Debrecen, Hungary,
Sept. 30 - Oct. 4, 200
Solution of the Skyrme-Hartree-Fock equations in the Cartesian deformed harmonic oscillator basis. (II) The program HFODD
We describe the code HFODD which solves the nuclear Skyrme-Hartree-Fock
problem by using the deformed Cartesian harmonic oscillator basis. The user has
a possibility of choosing among various symmetries of the nuclear HF problem
for rotating or non-rotating nuclei; they vary from the non-axial
parity-invariant nuclear shapes, through those also breaking the intrinsic
parity, towards the least-restrictive case corresponding to only one symmetry
plane. The code provides a solution for a complete superdeformed rotational
band in an A~150 nucleus within one CPU hour of the CRAY C-90 supercomputer or
within two-three CPU hours of a fast workstation.Comment: 30 LaTeX pages, 9 postscript figures included, submitted to Computer
Physics Communication
Pairing schemes for HFB calculations of nuclei
Several pairing schemes currently used to describe superfluid nuclei through
Hartree-Fock-Bogolyubov (HFB) calculations are briefly reviewed. We put a
particular emphasis on the regularization recipes used in connection with
zero-range forces and on the density dependence which usually complement their
definition. Regarding the chosen regularization process, the goal is not only
to identify the impact it may or may not have on pairing properties of nuclei
through spherical 1D HFB calculations but also to assess its tractability for
systematic axial 2D and 3D mean-field and beyond-mean-field calculations.Comment: 7 pages, 7 figures, Invited talk at the Workshop on New developments
in Nuclear Self-Consistent Mean-Field Theories, Yukawa Institute for
Theoretical Physics, Kyoto, Japan, May 30 - June 1, 2005, Yukawa Institute
for Theoretical Physics Report Series (Soryushi-ron kenkyu
Configuration mixing of mean-field wave-functions projected on angular momentum and particle number; application to 24Mg
We present in this paper the general framework of a method which permits to
restore the rotational and particle number symmetries of wave functions
obtained in Skyrme HF+BCS calculations. This restoration is nothing but a
projection of mean-field intrinsic wave functions onto good particle number and
good angular momentum. The method allows also to mix projected wave functions.
Such a configuration mixing is discussed for sets of HF+BCS intrinsic states
generated in constrained calculations with suitable collective variables. This
procedure gives collective states which are eigenstates of the particle number
and the angular momentum operators and between which transition probabilities
are calculated. An application to 24Mg is presented, with mean-field wave
functions generated by axial quadrupole constraints. Theoretical spectra and
transition probabilities are compared to the experiment.Comment: 26 pages, 7 figures. Submitted to Nuclear Physic
Superdeformed Bands of Odd Nuclei in A=190 Region in the Quasiparticle Picture
We study the properties of the superdeformed (SD) bands of 195Pb and 193Hg by
the cranked Hartree-Fock-Bogoliubov method. Our calculations reproduce the flat
behavior of the dynamical moment of inertia of two of the SD bands of 195Pb
measured recently. We discuss possible configuration assignments for the
observed bands 3 and 4 of 195Pb. We also calculate the two interacting SD bands
of 193Hg. Our analysis confirms the superiority of a density-dependent pairing
force over a seniority pairing interaction.Comment: 12 pages, 5 Postscript figures, submitted to Phys.Rev.
Tetrahedral and Triangular Deformations of Nuclei in Mass Region
We study static non-axial octupole deformations in proton-rich nuclei,
Ge, Se, Kr, Sr, Zr and Mo, by using
the Skyrme Hartree-Fock plus BCS calculation with no restrictions on the
nuclear shape. The calculation predicts that the oblate ground state in
Se is extremely soft for the triangular deformation, and that
in Zr the low-lying local minimum state coexisting with the prolate
ground state has the tetrahedral deformation.Comment: 8 pages, 4 Postscript figures, REVTE
GCM Analysis of the collective properties of lead isotopes with exact projection on particle numbers
We present a microscopic analysis of the collective behaviour of the lead
isotopes in the vicinity of Pb208. In this study, we rely on a coherent
approach based on the Generator Coordinate Method including exact projection on
N and Z numbers within a collective space generated by means of the constrained
Hartree-Fock BCS method. With the same Hamiltonian used in HF+BCS calculations,
we have performed a comprehensive study including monopole, quadrupole and
octupole excitations as well as pairing vibrations. We find that, for the
considered nuclei, the collective modes which modify the most the conclusions
drawn from the mean-field theory are the octupole and pairing vibrations.Comment: 10 pages LATEX, 8 figures, submitted to EPJ
Approximate particle number projection with density dependent forces: Superdeformed bands in the A=150 and A=190 regions
We derive the equations for approximate particle number projection based on
mean field wave functions with finite range density dependent forces. As an
application ground bands of even-A superdeformed nuclei in the A=150 and A=190
regions are calculated with the Gogny force.
We discuss nuclear properties such as quadrupole moments, moments of inertia
and quasiparticle spectra, among others, as a function of the angular momentum.
We obtain a good overall description.Comment: 31 pages, 10 figures, 3 appendices. In press in Nucl. Phy
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